When an item is Excluded from Generation, its source code is not generated. Project Item Templates and a few other Template Types may be excluded from generation of source code. This can be configured using their Excluded from Generation context menu option in the Project Explorer.
When project items are Excluded from Generation, this is indicated by the Project Explorer using Text color status indication. When Excluded from Generation is turned on for an item, the icon for this option is highlighted in the item's context menu.
Excluding an item from generation stops the template from generating new source code, but old source code generated by the template may be left in the project's output folder, affecting the compilation process. Using the Clean output folder link in the Build Page usually helps in this case.
Re-including items in generation
An item can be re-included in generation by selecting the option once more from its context menu.
See also
Project items can also be Excluded from Build, generating their source code, but not building it.